Detecting a file type from an unknown document - 100% Free

Determine the file type, file extension, and MIME type based on the file contents

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Get file type information based on the file contents


Have you ever found a file on your computer without an extension or has an incorrect extension? helps you determine the true file type of any file based on the content of the file, not the extension. Simply use our online tool to upload the file and we will test it and show you the results.

CheckFileType does not require an e-mail or registration. The purpose of this site is to provide a quick tool to help you determine the file extension for an unrecognized or unknown filetype.

What is a file type?
Every file has a particular format. Files are either binary or ascii. Common ascii files would be simple text or more complicated formatted text such as PDF or XML. Common binary files are images (jpeg, gif, png) or compressed files. But the file formats can be layered, such as DOCX or PPTX. These are a collection of ascii XML files in a zip archive which makes it a binary file.

In some cases such as zip files this tool may search the contents of the archive to give you the file type of each file contained in the archive.

About your privacy
We store your file temporarily for processing, and then once it is completed we remove the file.